Influence of Baking on Thermal–Expansion Ability of Quartz Sands

2011 ◽  
Vol 211-212 ◽  
pp. 1226-1229
Author(s):  
Hai Ou Jing ◽  
Shu Hua Wang
Keyword(s):  
Thermal Expansion ◽  
Expansion Ratio ◽  
Test Results ◽  
Quartz Sands ◽  
Expansion Ability ◽  
Changing Tendency

In order to understand the changing tendency of thermal–expansion abilities of used sands in foundry, the four groups of quartz sands were measured in this paper. The influencing laws of baked-times and temperatures on the property of quartz sands were analyzed. And the test results showed that volume thermal-expansion ratio of quartz sands decreases with increasing of the baked-times.

scholarly journals Carbon Fibre - Copper Composites Obtained by Foil Casting

1994 ◽  
Vol 3 (2) ◽  
pp. 096369359400300
Author(s):  
W.K. Wtosiński ◽  
W. Olesińska ◽  
K. Pietrzak ◽  
D. Kaliński
Keyword(s):  
Thermal Expansion ◽  
Carbon Fibre ◽  
Casting Process ◽  
Fibre Content ◽  
Resistance Welding ◽  
Test Results ◽  
Micro Hardness ◽  
Electric Contacts

A method for production of carbon fibre - copper composites by foil casting is presented. As follows from the test results included, the foil casting process may be applied to produce the carbon fibre -copper composites. Thanks to the use continuous fibres, the method allows to obtain composites with fibres ordered directionally. Measurements of thermal expansion and micro-hardness of a composite with 30% fibre content, as well as examination of its microstructure are presented. The composites may, among others, find application in manufacturing of electrodes for resistance welding, electric contacts and expansion wafers for semiconductor power components.

Turbocharger Turbine Rotor Design for Low U/C Values

2019 ◽  
Author(s):  
Hua Chen ◽  
Yuchao Song ◽  
Aiguo Gu ◽  
Yangfang Zhang ◽  
Hongwei Li
Keyword(s):  
Internal Combustion Engines ◽  
Mechanical Design ◽  
Turbine Rotor ◽  
Expansion Ratio ◽  
Test Results ◽  
Rotor Design ◽  
A Value ◽  
Emission Regulations ◽  
Blade Tip ◽  
C Value

Abstract Emission regulations worldwide demand better low-end torque from internal combustion engines. This pushes the operating condition of turbocharger turbine to lower U/C values, where U is the blade tip speed and C is the turbine isentropic spouting velocity which increases with turbine expansion ratio. Traditional radial and some mixed flow turbines, dictated by their rotor design, have their efficiency peaks at U/C value around 0.70, a value considerably larger than desired. In this paper, we deliberate the measures to shift the peak efficiency of turbine rotor toward a lower U/C value than 0.7. The underlying physics of these measures are first explained, CFD and test results where available are then given. Implications to mechanical design, manufacturing and others are also discussed. Finally, an example of a turbine rotor design is given implementing these measures. Test results showed better efficiency was obtained from the design at lower U/C values than from the baseline.

Effect of Si3N4-Nd2O3 Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

2011 ◽  
Vol 335-336 ◽  
pp. 728-731
Author(s):  
Shu Bin Shen ◽  
Jing Long Bu ◽  
Li Xue Yu ◽  
Shu Long Liu ◽  
Zhi Fa Wang
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Expansion Ratio ◽  
Quartz Ceramic ◽  
Apparent Porosity ◽  
Raw Material ◽  
Ratio Analysis ◽  
Fused Quartz

Fused quartz granules (d50=19 μm) were used as raw material, and Si3N4-Nd2O3 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were studied and the samples were further analysed by means of XRD and SEM. The results showed that the sample sintered at each temperature with 3% Si3N4-Nd2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Si3N4-Nd2O3 was useful to the sintering of fused quartz ceramic materials. The results of XRD and thermal expansion ratio analysis showed that 3% Si3N4-Nd2O3 compound additive had better effect on inhibiting crystallization of the samples sintered at 1300 °C, 1350 °C and 1400 °C.

scholarly journals The Sticking Out Mechanism and Growth of TiB Whiskers from TiBw/Ti-6Al-4V Composites during Sintering

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1467
Author(s):  
Guorong Cui ◽  
Bo Yang ◽  
Jiabin Hou ◽  
Wenzhen Chen ◽  
Wencong Zhang
Keyword(s):  
Thermal Expansion ◽  
Interfacial Strength ◽  
Expansion Ratio ◽  
Low Energy ◽  
The Other ◽  
High Concentration ◽  
Near Surface ◽  
The Matrix

The process of TiB whiskers (TiBw) squeezed out and the growth of sticking out TiBw were investigated in TiBw/Ti-6Al-4V composites via adding 5 vol% TiB2 powders. TiB2 distributed along the surface of Ti-6Al-4V powders by low energy milling, resulted in the enrichment region of B and Ti elements. During sintering, TiBw nucleated and grew along the [010] direction with the diffusion of B and Ti atoms in the enrichment region. Due to larger thermal expansion ratio of TiBw, the TiBw were squeezed out from the Ti matrix, and the sticking out TiBw grew gradually with the diffusion of B and Ti atoms from the enrichment region. Because of the high interfacial strength between TiBw and Ti matrix, the matrix adhered to TiBw, and hindered the squeezing out of TiBw. Eventually, the cone TiBw stuck out the Ti matrix, and the other end of TiBw pinned in Ti matrix. Moreover, the diameter of TiBw near surface between TiB2 and Ti matrix was larger than other areas, resulting from the high concentration of B and Ti atoms. The solubilized B atoms near TiBw were absorbed by TiBw, which was considered as the other B source of TiBw.

Effect of B4C-Yb2O3 Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

2011 ◽  
Vol 291-294 ◽  
pp. 24-28
Author(s):  
Shu Bin Shen ◽  
Jing Long Bu ◽  
Li Xue Yu ◽  
Zhi Fa Wang ◽  
Rong Lin Wang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Xrd Analysis ◽  
Expansion Ratio ◽  
Quartz Ceramic ◽  
Apparent Porosity ◽  
Raw Material ◽  
Obvious Effect ◽  
Fused Quartz

Fused quartz granules (d50=19 μm) were used as raw material, and B4C-Yb2O3 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1250 °C, 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were examined and they were analysed by means of XRD and SEM. The results showed that the sample sintered at each temperature with 3% B4C-Yb2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% B4C-Yb2O3 was conducive to sintering of fused quartz ceramic materials. The results of XRD analysis and thermal expansion ratio analysis showed that 3% B4C-Yb2O3 compound additive had obvious effect on inhibiting crystallization of the samples sintered at various temperatures. It can be deduced that the 3% B4C-Yb2O3 compound additive plays the excellent role in inhibiting crystallization and facilitating sintering of fused quartz ceramic materials.

Study and Experiments of a Small Radial Turbine for Auxiliary Power Units

1986 ◽  
Author(s):  
Y. Ribaud ◽  
C. Mischel
Keyword(s):  
Guide Vane ◽  
Expansion Ratio ◽  
Test Results ◽  
Radial Turbine ◽  
Auxiliary Power ◽  
Nozzle Guide Vane ◽  
Blade Shape ◽  
Auxiliary Power Units ◽  
Turboshaft Engine ◽  
Nozzle Guide

The design of a small inward flow turbine with a 3.6 expansion ratio has been undertaken by MICROTURBO, in cooperation with ONERA for calculations and test results analysis. Initially, the purpose and constraints of this study are underlined. Preliminary calculations have led to the design of the blade shape of the Nozzle Guide Vane and of the rotor. Following this, the results of the quasi-3D-flow computations, performed for the stator and the rotor, are given. Both the cold bench tests on this turbine and the corresponding hot tests on the turboshaft engine enable performances to be checked. The value of the calculations is confirmed when we look at the high total and static adiabatic efficiencies obtained. These good results are encouraging for the future use of this kind of turbomachine.

Analysis of Temperature Effects on a Fully-Symmetrical Micromachined Gyroscope

2009 ◽  
Vol 60-61 ◽  
pp. 31-35
Author(s):  
Wei Ping Chen ◽  
Yu Gang Guo ◽  
Xiao Liang Chen ◽  
Hong Chen ◽  
Zhen Gang Zhao
Keyword(s):  
Thermal Expansion ◽  
Temperature Effects ◽  
Test Results ◽  
Resonant Frequencies ◽  
Resonance Frequencies ◽  
Environment Temperature ◽  
Good Accordance ◽  
Simulation Results ◽  
Effects Of Temperature ◽  
Micromachined Gyroscope

This paper researches on the temperature effects of a fully-symmetrical micromachined gyroscope. The Young’s modulus and thermal expansion coefficient of silicon vary with the environment temperature, which affects the modes’ resonant frequencies of micromachined gyroscopes. The effects of temperature fluctuation on the modes’ resonant frequencies is simulated by the FEM software ANSYS. The simulation results show that the fully-symmetrical gyroscope’s resonance frequencies decrease with the increase of temperature and the decrease degree nearly 0.256Hz/°C, but the two modes’ resonance frequencies matches well. The micromachined gyroscope’s dynamic characteristics are tested. The resonant frequencies and the quality factor are reduced with the increase of temperature and the decrease degree of the fit linear about the resonant frequencies is 0.276 Hz/°C. The test results are in good accordance with the simulation results.

Study on Preparation of High Strength Gypsum by Flue Gas Desulfurization Gypsum

2013 ◽  
Vol 405-408 ◽  
pp. 2681-2685
Author(s):  
Ji Xiu Zhang ◽  
Peng Xuan Duan ◽  
Ye Zhang
Keyword(s):  
Thermal Expansion ◽  
Power Plant ◽  
Product Development ◽  
Flue Gas ◽  
Thermal Power Plant ◽  
Thermal Power ◽  
High Strength ◽  
Flue Gas Desulfurization ◽  
Test Results ◽  
Fgd Gypsum

In this paper, the flue gas desulfurization gypsum (FGD) generated from thermal power plant is used to produce high strength gypsum. The basic properties of super high strength gypsum prepared by FGD gypsum are investigated based on the test results of strength, thermal expansion rate, crystal appearance and size. The results indicate that the properties of high strength gypsum prepared by FGD gypsum above α50 standard. This can be a reference for gypsum-based α super high-strength gypsum related product development.

Experimental Research on Brittle Shale Failure Caused by Drilling Fluid Activity

2013 ◽  
Vol 807-809 ◽  
pp. 2550-2553 ◽  
Author(s):  
Ming Wang Peng ◽  
Hang Wen ◽  
Wei Zhou ◽  
Zhao Jun Wen ◽  
Xiao Ming Liu ◽  
...  
Keyword(s):  
Internal Structure ◽  
Experimental Research ◽  
Rock Strength ◽  
Drilling Fluid ◽  
Expansion Ratio ◽  
Wellbore Stability ◽  
Test Results ◽  
Fracture Formation ◽  
Set Up ◽  
Activity Window

The crack formed under the action of circular medium fluid around the wellbore of brittle shale has been a hot issue in recent years. This paper considers the brittle shale micro fracture formation mechanism from the perspective of inhibitive ability of drilling fluid activity. The model of activity-swelling-hydration is set up firstly through revising generalized Usher model, it states the drilling fluid activity range to keep wellbore in osmotic hydration stage with the critical expansion ratio, thus puts forward the concept of activity window and is verified by indoor test. Results show that the different activity of drilling fluid brings difference in rock strength in macro and time sensitive effect for internal structure of rock in micro. This mechanism can provide a more accurate range design for drilling fluid activity and strong guarantee for wellbore stability.

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